Fair-haired, square jawed and irresistible to women, Flash Gordon is the great American hero personified. Alex Raymond managed to upstage Buck Rogers in the comic strips with his sense of adventure, and ever-changing perils.
Though not providing much in terms of direct influence on Star Wars, Buck Rogers is nonetheless vital to the evolution of science fiction as we know it, not to mention comic books.
Not long out of USC, Coppola's production company American Zoetrope, started its life with Lucas's first feature film, THX 1138. The art house precursor of Star Wars.
Published so rarely that it's never actually been published yet.
May the force be with you.